What is the expected outcome of a test cross?

A test cross is a genetic cross performed to ascertain the genotype of an individual expressing a dominant phenotype. Since the dominant phenotype can result from either homozygous dominant or heterozygous genotypes, a test cross involves mating the individual in question with a homozygous recessive individual. The offspring produced from this cross will exhibit specific traits depending on the genotype of the dominant individual.

If any offspring display a recessive phenotype, it confirms that the dominant phenotype individual is heterozygous, as the presence of the recessive trait indicates that a recessive allele must be present in the parental genotype. On the other hand, if all offspring display the dominant phenotype, the individual is likely homozygous dominant, confirming that no recessive alleles are carried.

This method is crucial in genetics for understanding inheritance patterns and the specific makeup of an organism's genes. The other options mention determining phenotypes, predicting offspring traits, or identifying recessive traits broadly, but these do not capture the specific intent of a test cross as accurately as determining the genotype of an individual with a dominant phenotype does.